Needleless injector



Aug. 19, 1969 A, zlMMET ETAL NEEDLELESS INJEcToR Filed March 14, 1966ARTHUR 1.. zlMMET By R|cHARD H. HUBBARD ATTORNEY United States Patent O3,461,867 NEEDLELIESS INJECTOR Arthur L. Zimmet, New York, N.Y., andRichard H. Hubbard, Clifton Forge, Va., assignors to Mizzy, inc.,Clifton Forge, Va.. a corporation of New York Filed Mar. 14, 1966, Ser.No. 534,187 lint. Cl. Alm 3.7/

US. Cl. 128--173 3 Claims ABSTRACT 0F THE DISCLGSURE A needlelessinjector, and more particularly an improved device of the typedescribed, which includes an elongated body having a front and rearportion with the front portion having an elongated recess within theconfines thereof to receive an ampule that defines a liquid reservoir.The reservoir is in communication with a pressure chamber which ischarged by the retraction of a piston associated therewith and which isdischarged upon rapid advance of such piston, through a dischargepassageway at the end of the front portion which forms an obtuse anglewith respect to said body.

More particularly, this invention relates to an improved injector of thetype wherein an innoculant is discharged at high velocity through a jetorifice, to penetrate the tissues of the patient.

The invention, in its more particular phases, relates to an improvedinjector wherein an innoculant is stored in a readily replaceable ampuleor container, which may be applied to the device, forming a reservoirtherefor, the device including means for withdrawing from the reservoirselected quantities of innoculant, the same being stored at anintermediate chamber directly before it is dispensed.

The invention further relates to an improved injector apparatusincorporating a novel valving arrangement interposed between thedischarge orifice and the reservoir, whereby contamination of thecontents is avoided.

The invention further relates to an improved apparatus of the typedescribed wherein the quantity and velocity of innoculant dispensed maybe readily controlled, and wherein it is assured that the entirequantity of innoculant is expressed under sufficient pressure to enterthe tissues to be treated.

Accordingly, it is an object of the invention to provide an improvedneedleless injector.

To attain these objects and such further objects as may appear herein orbe hereinafter pointed out, reference is made to the accompanyingdrawings, forming a part hereof, in which:

FIG. l is a plan view of an injector device in accordance with theinvention;

FIG. 2 is a section taken on line 2-2 of FIG. l;

FIG. 3 is a magnilied, fragmentary section showing the position of theparts when the same are partially cocked; and

FIG. 4 is a further magnified section of the discharge assembly, showingthe position of the parts during the fluid expressing stroke.

In accordance with the invention, 1t) is an injector mechanismcomprising a body 11 having a first axially extending bore '12. The boreincludes a wide diameter portion 13 and an axially extended narrowdiameter portion or discharge chamber 14. The body includes a separablereservoir which, in the illustrated embodiment, comprises a disposableampule 1S, removably insertible into a holder defined by the bodyportion. The ampule is formed of a glass cylinder 16 provided withafixed, penetrable seal 17 at one end, the seal preferably being of iceelastomeric composition. A movable seal 18 is disposed in the other endof the cylinder, it being understood that the seal 1S is shiftableaxially within the ampule. The ampule is mountable within a recess 19defined in the body portion, a hollow needle 20, extending axially fromthe body portion and providing an exit means for the ampule contents,being insertble through 'the seal 17.

The inner terminal end 21 of the needle 2@ defines a frusto-conicalseat, a ball 22 being normally pressed by spring 23 into contact withthe seat. A duct 24 extends from the check valve dened by the ball 22and seat 21, the duct leading into the discharge chamber 14. A passage25 leads from the discharge chamber v14 to the ejector head, referred togenerally as 26.

The liuid within the ampule 15 is maintained under pressure by a springpressed ram 27, having a ram head 28 of a size which will permit saidhead to enter into the cylinder 16 and follow the movable seal 1S asfluid is progressively discharged from the ampule.

The ram 27 includes a mounting knob 29, having an offset locking pin 30and an inwardly extending spring guide 31. The ram spring 32 is sleevedover the guide 31, the forward end of the spring pressing against aninternal plug 33 extending rearwardly from the head 28 of the ram.

The body 11 of the injector device is provided with a bayonet slot 34adjacent the rear end 35 thereof to receive the pin 3() to retain theram 27 in position.

From the foregoing it will be understood that an ampule may be loadedinto the recess 19 by pressing the same axially over the needle 2t? sothat the needle penetrates the seal 17, seating the ampule within therecess. Thereafter, the ram 27 is inserted endwise behind the ampule,the retainer knob 29 being pressed inwardly to permit the locking pin3i) to enter bayonet slot 34 in the body p0rtion, the knob 29 beingthereafter twisted to cause the pin 30 to enter the bayonet slot 34 andprevent outward movement of the knob. The ram spring 32 will becompressed by the aforesaid loading action, causing the ram head 28 tobe urged tightly against the rear seal 18 of the ampule.

A piston assembly is disposed in the axially extending bore 12, theassembly including a piston head 40 and a plunger assembly 41. Thepiston head 40 extends slidably and sealingly within the narrow boreportion 14, the head 40 defining a rearwardmost movable boundary of thedischarge chamber 14.

The piston head 40 is formed on the forward end of a piston rod Imember42, the rear end of which comprises a threaded shank 43. A releasecollar 44 is threaded over the shank 43 and includes a forwardlydirected annular shoulder 4S. The collar, in addition, in the portionsurrounding the shank 43, defines a rearwardly directed spring supportshoulder 46. The large diameter bore portion 13 adjacent the outer end35 of the body portion incorporates an internally threaded portion *47,an annular spring compression collar 48 being threaded into the portion47 of the bore 13.

A piston actuator spring 49 is compressed between the shoulder 46 ofcollar 44 and a forwardly directed shoulder 50 of compression collar 48.It will be understood that by forwardly or rearwardly Amoving thecompression collar `48 within the body portion, the degree ofcompression applied to the spring 49 may be varied.

A spring adjustment member 51 is seated in the end of the bore 13, theadjustment member incorporating spaced drive teeth 52 which mesh withrecesses 53 formed in the adjustment collar 48. Thus, it will be seenthat rotation of the adjustment member 51 will communicate rotarymovement to the collar 48, while still permitting relative axialmovement between these parts.

A stroke adjuster nut 54 is threaded over the outer portion 55 of thepiston shank 43, the nut 54 including a forwardly directed stop shoulderportion S6. The spring adjustment member 51 includes a rearwardlydirected complemental stop shoulder 57.

From the foregoing, it will be seen that the forwardmost position whichmay be reached by the piston is limited by the engagement of thecomplemental stop shoulders 56, 57 of the nut 54 and adjustment member51 respectively. Optionally, the outermost surface of the nut 54 may bemarked with indexing numerals or the like, to provide a ready means ofidentifying the quantity of fiuid which will be expressed in any strokeof the piston.

A cooking lever 60 is pivotally mounted on a pin 61 carried by the bodyportion. The cocking lever includes spaced claw members 62, 62 which arepivoted into the interior of the body portion through access slots 63formed in said body portion, when the lever is lifted to the positionshown in FIG. 3. As best shown in FIG. 3, lifting of the lever causesthe claws 62 to bear against shoulder 45, causing the piston shank, rodand head to be shifted rearwardly or to the right, as shown in thedrawings.

A detent trigger 64 is pivotally mounted on the body portion, theforward end 65 of the trigger being normally pressed away from the bodyportion by a leaf spring 66. A detent shoulder 67 engages the shoulder45 of the release collar 44 when the collar has been shiftedsufficiently rearwardly, it being understood that the trigger willmaintain the collar and associated piston mechanism in the rearwardposition until the trigger is tripped by pressing the end 65 toward thebody portion of the injector against the force of spring 66.

As best seen in FIG. 4, the ejector head 26 includes a jet orifice 70.The orifice 70 is formed in an insert member 71 threaded into the head26, the portions 72 of the insert member immediately rearward of theorifice 70 defining a discharge valve seat. A valve stem 73 of generallycylindrical conformation is movably mounted within a bore '74 in thedischarge head 26. The stem 73 includes a reduced cylindrical tailportion 75, about which is concentrically mounted a compression spring76. A spring seat 77, threaded into the end of the head 26 remote fromthe orifice 70, bears against one end of the compression spring 76,causing the opposite end of said spring to urge the tapered end 78tightly and sealingly against the valve seat 72, `as shown in FIG. 2.

The passage 25 leading from the discharge chamber to the head 26communicates with an oversize cylindrical recess 79 formed in the insert71, thus permitting the flow of fiuid into contact with those portionsof the valve stem which lie outwardly of the points of engagementbetween the valve stem and the valve seat. It will thus be seen thatsufficient pressure in the area 79 will tend tourge the valve stem 73rearwardly to clear the valve stem 73 from the valve seat 72.

OPERATION An ampule 16 is loaded into the device in the mannerpreviously set forth. The cocking lever is withdrawn as shown in FIG. 3,shifting piston rod 42 and piston head 40 rearwardly within the bore 14.The rearward movement of the piston creates a vacuum in the dischargechamber 14, and the cumulative result of this sub-atmospheric pressure,plus the pressure applied to the ampule by the ram 27 causes a fiuidflow through the needle 2G and the duct 24 into the discharge chamber14. The pressure required to unseat the valve stem 73 is greater thanthat required to unseat the ball valve 22 and, thus, the stem remains inhead-sealing position throughout the cocking operation.

With the plunger in cocked position, the trigger 54 may be depressed,causing the piston assembly to snap forwardly and creating an extremelyhigh pressure head within the discharge chamber 14. Such pressure can berelieved only by unseating the valve stem 73 from the valve seat 72since pressure in such chamber tends more firmly to seat the ball 22 inthe seat 21. When the pressure in the chamber 14 reaches a sufficientlyhigh value, the stem 73 will be shifted rearwardly against the pressureof spring 76, causing iiuid in the chamber 14 to be violently expressedthrough the jet orifice 70. When the pressure is relieved at the end ofthe forward movement of piston head 40, the spring 76 will immediatelycause the stem 73 to be shifted against its seat, preventing any backfiow or contamination of the contents of the injector.

As previously noted, the forward movement of piston head 40 and hencethe quantity of fiuid expelled may be controlled by rotation of nut 54.In addition, the ejection pressure may be varied by modifying thecompression of spring 49. This is readily accomplished by rotation ofspring adjustment member 51 which in turn controls the position ofspring compression collar 48.

A highly desirable feature of the device lies in the employment of therelief valve (72, 73) in the head 26. 'Ihe value of such valve will bereadily appreciated when the device is contrasted with units heretoforeknown wherein the reduced size of the discharge orifice provides thesole limitation to the flow of liquid `after release of the piston. Insuch devices, it is possible for the initially discharged portions ofthe liquid to be expelled at an undesirably low pressure, and for thedesired tissue penetrating pressure to be attained only at anintermediate portion of the stroke of the piston. Under suchcircumstances, it will be readily recognized that the initially emergingportions of the fluid may not penetrate the tissue. Thus, in such knowndevices, the effective dosage, namely, the dosage expressed at a forcesufficient to penetrate, will bear no necessary relation to the totalquantity of fluid expressed.

In contrast, the device of the present invention, by providing an exitvalve directly adjacent the jet orifice, assures that only fluidsufiiciently compressed to cause unseating of the valve stem will emergefrom the orifice so that there will be a high velocity at the end of theinjection as well as at the beginning. Therefore, all emerging fluidsare assured to have attained a predictably high tissue penetratingvelocity. Furthermore, by reason of the exit valve, the injector willhave a dripless cut-off and in addition, the instrument will be sealedfrom the atmosphere insuring against any back flow or contaminationreaching the remaining injectable material.

It has been further found that by providing a valve stern which, inmoving to the opening position shifts in a direction opposite to thedirection of fluid movement, a sudden initial surge of high velocity isobtained, which assures particularly effective application of the uid.

From the foregoing, it will be recognized that the injector apparatus issimple to use, efficient in operation and may be readily disassembledfor sterilization. Furthermore, the quantity of uid which is expressedin each stroke of the piston may be accurately determined and, by reasonof the novel construction of the device, the expelled fluids areeffectively and predictably administered, as contrasted with injectorsheretofore known.

As many changes could be made in the above construction, and manyapparently widely different embodiments of this invention could be madewithout departing from the scope of the claims, it is intended that allmatter contained in the above description or shown yin the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

Having thus described our invention, what we claim as new and desire tosecure by Letters Patent of the United States is:

1. A needleless injector of the piston actuated type comprising `a bodyhaving a front portion and a rear portion, the front portion beingelongated and of smaller cross section than said rear portion, the frontportion of said body having an elongated cavity within the confinesthereof releasably to receive a variable volume ampule defining L.. J aliquid reservoir for storing iiuid, holding means for removablygrip-ping said ampule, spring means shiftable into said ampule forpressurizing the contents thereof, said ampule and said spring meansbeing within the confines of said body, a duct leading from saidreservoir, oneway valve means in said duct for blocking luid flowthrough said duct toward said reservoir and permitting tlow out of saidreservoir, an axial passageway dening a discharge chamber, said ductcommunicating with said passageway, an axially movable plunger shiftablein said passageway and defining a movable boundary of said chamber forselectively increasing and decreasing the volurne of said chamber, saidplunger being in parallel longitudinal relationship with respect to saidampule, spring means biased between a spring seat on said body and saidplunger urging said plunger toward said chamber, a stop shoulder on saidbody portion, an adjustment member axially movably mounted on saidplunger, said last named member being disposed in the path of movementof said shoulder as said plunger moves axially toward said chamber, saidshoulder and adjustment member, in the engaging position thereof,blocking further movement of said plunger into said chamber, whereby theaxially adjusted position of said member with respect to said plungerdetermines the stroke of said plunger, a discharge head mounted at thefree end of said front portion, said discharge head having a dischargepassageway with a jet orifice at its outer end, said passageway formingan obtuse angle with respect to said body portion and pressure sensitivevalve means interposed between and normally isolating said orifice fromsaid chamber, said valve means being effective to provide communicationbetween said orifice and chamber responsive to pressures in saidcharnber of a predetermined magnitude.

2. A device in accordance with claim 1 wherein the terminal end of saidduct remote from said passageway comprises a hollow needle insertibleinto the interior of said ampule.

3. A device in accordance Iwith claim 1 wherein said spring seat isaxially movably mounted relative to said body, thereby to vary thecompressive force exerted by said spring means against said plunger inaccordance with the axially adjusted position of said spring seat withrespect to said body.

References Cited UNITED STATES PATENTS 9/1963 Morrow et al. 128-2187/1964 lsmach 12S-173

